This application claims the benefit of priority to Japanese Patent Application Nos. 2003-140567 and 2003-180365, herein incorporated by reference.
1. Field of the Invention
The present invention relates to an input device for outputting an operation signal for operating an electronic apparatus such as an in-vehicle electronic apparatus. More specifically, the invention relates to a force feedback input device having a knob that provides a predetermined dynamic sensation (force sensation) to the operator by applying a turning force to the knob in accordance with the turning angle.
2. Description of the Related Art
A known force feedback input device comprises a knob to be rotated manually, a rotary encoder for detecting the turning angle of the knob, a motor for applying a turning force to the knob, and a controller for controlling the motor in accordance with the turning angle of the knob detected by the rotary encoder and for outputting an operating signal corresponding to the turning angle of the knob to a separate device which is controlled by the knob.
By manually rotating a knob, the force feedback input device outputs an operating signal for operating an electric apparatus such as an in-vehicle electric apparatus. By operating the knob of the force feedback input device, for example, the airflow of an in-vehicle air conditioner may be controlled, the air outlet of the in-vehicle air conditioner may be switched, the volume and the tuning of the radio may be controlled, and the volume and the tone of the audio equipment may be controlled. Furthermore, the force feedback input device is applied in a so-called steer-by-wire system, which is installed on a steering apparatus to steer the vehicle and provide force feedback from the tires.
To control the air flow from an in-vehicle air conditioner, the knob is set, for example, so that when it is turned in a direction that increases the air flow, a motor applies a turning force to the knob in a direction opposite to the direction the knob is turned. In this way, as the knob is turned in the direction to increase the air flow, the turning force applied in the direction opposite to the direction the knob is turned is increased. In other words, the operator can sense how much he or she has turned the knob in the direction to increase the air flow through the increase in a sensation of resistance (force sensation) provided by the knob.
As well as the above-mentioned force feedback input device that provides a sensation of resistance as a force feedback, other force feedback input devices are known that provide a sensation of acceleration as a force feedback by applying a turning force in the direction the knob is turned or provide a sensation of clicking as a force feedback by reversing the turning force applied to the knob when the turning angle of the knob becomes greater than a predetermined turning angle, as is disclosed in Japanese Unexamined Patent Application Publication No. 2003-50639.